Steam-engine valve-gear.



W. S. BROWN STEAM ENGINE VALVE GEAR. APPLICATION FILED JULY 11, 1911.

1,Q33,53'2, I Patented July 23,1912.

1 Fig. 1

W. QJIINVE/VTOR WITNESSES WILLIAMSHERMAN BROWN,- OF KNOXVILLE, TENNESSEE.

STEAM-ENGINE VALVE-GEAR.

To all whom it may concern:

Be it- 'known that I, WILLIAM SHERMAN BROWN, a citizen of the United States, residing at Knoxville, in the county of Knox and State of Tennessee, have invented a new .and useful Im rovement in Steam-Engine Val.e -Gear, 0 which the following is a specification, reference being hadto the accompanying drawing.

My improvement relates the crank of a drive wheel of a steam locomotive to the distributing valve which admits steam to the cylinder.

The object'of my improvement is to provide a construction whichis simple, has the parts accessibly lo'cate'd, and which avoids irregularity of valve action due to lost metion'or pounding at'the crank;

In the accompanying drawings, Figure 1 'is a side elevation, portions being-broken away, showing my improvement applied to chest.

one side of a locomotive; Figr-Z-isa plan of a'portion of the mechanism; shown by ;Fig.1;Fi 3 is asectiiinonthe line, 3-5-3, of Fig; 2,1ooking tOWaId@tlfl6'1lgl1t; Flg. 3': is a section on the line, of ltig. 2,-looking towardtheleft; Fig. 4 is a section on the line, 44, of Fig. =2,-'looking in the direction of the arrow ;-;'Fig, his a section on the line, 5'5, ofl ig 2,;lookin'g toward the ri ht. i

flleferring to said drawings, 1, ;is the cylinder, 2, is the-valve chest, 3, is the slide valve located within said chest, and 4, is the usual valve stem extending through said The ordinaryipiston, 8, is located within "said cylinder, and has applied to it the ordinary piston rod, 9, w ich is joinedto the ordinary cross-head, 10, confined between the. usual horizontal parallel guidebars, 7. To said cross-head is coupled one end of theusual connecting rod or pitman, 11, the other end of said rod being coupled to the usual main crank, 12, carried by a drive wheel, D. 7 On the main crank, 12, is

I rigidly mounted an auxiliarycrank, 13. To

said auxiliary crank is coupled one end of the auxiliary pitman-rod, 14; To the upper portion of the rear face of the. ordinary gu1de-yoke, 15, is secured a U-sh'ape bracket, 16, the body of which is placed flatwise againstsaid face of said yoke. Two arms, 17 and 18, extend rearward from said body in planes which are upright and perpendicu- Speeification of Letters Patent.

Application filed July 1!, 1911. Serial No. 638,00

particularly to- 'mechanism for transmitting motion from Patented July 23, 1912.

v lar to the plane of said yoke. In the upper portion of each arm is a bearing, 19, receiving the ends of a shaft, 20. On saidshaft is a bell crank or rocking member, 21,-preferably secured rigidly to said shaft by means of a set bolt, 22, so as to compel turning of said shaft in the bearings, 19. Said bell crank has two horizontal arms, 21*, and 21 depending arm, 21*. The latter arm is coupled to the valve stem, 4. By -rocking the bell crank, the valve stem is reciprocated.

" An approximately upright link, 21"), has

its upper end coupled to the arms, 21*, of

the'bell crank, while its lower end is coupled to the forward end of the auxiliary pitman rod, 14, both ends of said link being forked to receive said rod and said arms, as shown by the drawings.

A cross-beam or plate, 24,- extends' crosswise of the locomotive and is suitably secured to the framing, F From said crossbeam, 2. bridge-piece, 25, extends forward Said bridge-piece 18 m to the bracket, 16.

the form of a plate having its body set in an upright plane and having its rear end 1 turned to a right angle and secured to the cross-beam, 24, of the'engine frame, by bolts or rivet-s, 26, while its forward end is similarly turned to a right. angie and secured to the bracket, 16, by similar bolts or rivets', 26. Said bridgepiece extends end of'said link is coupled to the auxiliary pitman rod,14,byabolt,31. The slot, 28, is preferably made concentric with an axis which intersects a line which is an extension beneath the hub of the bell crank, 21.

of the cylinder axis and cuts the axis of the drive-wheel, D; and the length of said link, 30, is such as to allow the axis of said bolt to become coincident with the axis to which said slot is concentric. An approxil'nately horizontal link, 32, is couplodby it for' ward end to the slide bloc c. 29 and by its rear end to the arm, 33, which is rigid on a rock shaft, 34, supported in bearings, 35. On said rock shaft is an arm, 36, to which iscouple working on a sector or quadrarii, 39.

In operation, the slide block, 29, is set in any desired position in the slot, 28, by

means of the reversing lever, and While lot said block is so set the link, 30, oscill ates on said block with each reciprocation of the auxiliary pitman rod, the axis of the bolt,

31, moving in an arc in which lies the: axis to when the drive wheel is on either the front or the rear quarter. In Fig. 1, it is shown on the front quarter. Durin each such reci rocation, 'said pitm'an r rocks bodily with the axis of the bolt, 3l,'as a fulcrum. This involves the rising and falling of the forward end of said auxiliary rod and during such movementof said end or said rod, the link, 23, is forced up. and down and such movement of said link causes the rockingot the bell crank, 21, an'dthe reciprocation of the valve stem, 4. The gear is reversed, by throwing the reversing lever across the center in the usual manner, and the opening of the valve isvaried by movg the slide block nearer to or farther from the middle of the slot, 28, this being accomplished by the aidvofsuitable notches (not shown) on the reversing-lever sector. When the slide block is on the middle of said slot, the valve motion is reduced to the extent of the lead. The relation of the parts ofthemechanism is such as to cause the desired quick movementof the valve during the opening and closing.

It is to be observed that'my improvemen eliminates from the valve mechanism the eccentric and also all parts,having a high velocity. No part of the valve mechanism is connected to the connecting rod nor to thecross-head. Movement is transmitted to the valve stem from the wrist of the auxiliary crank and said wrist travels in -a relatively 'small'circle. Thus the movement .of the auxiliary rod and the links, 23, andT 30,

urthermor-e it is to be noted that lost motion due to wear at the wrist of the auxiliary crank will chiefly modify the lengthwise movement of the auxihary pitman, 14,

while the movement transmitted through the link, 23, is approximately at right-angles to said auxiliary pitman. Hence the modification of the longitudinal movement of said pitman is substantially not transmitted to said links And it will be seen that such modification of the rocking movementof the auxiliary pitman due to wear at the wrist of the auxilary crank will affeet the link, 23, in minimized form, because the portion of the auxiliary pitman .between the axis, .31, and the link, 23, is

much less than between said axis and the wrist of the auxiliary crank. In this connection it is to be remembered that wear by the auxiliary crank wrist in the auxiliary pitman is chiefly in the direction of the the bolt, 31, is'such as to length of said pitman. Such wear produces what is termed lost motion or pounding at the crank.

I claim as my invention,

1. In a steam engine valve gear, the combination of a slide block, means for moving said block, an auxiliary crank, an auxiliary rod coupled to said crank, 'f and two approximately upright links, each having its lower end coupled to the auxiliary rod and one having its upper end coupled to said slide block and the other having its upper end in operative relation with the. distributing valve, substantially as described.

2. In a steam engine valve gear, the combination of a slide block, means for moving said block, 'a bell crank in operative relation with the distributing valve, an auxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links each having its lower end coupled to 'end coupled to said slide block and the other having its upper end coupled to said bell crank, substantially as described.

3. In a steam engine valve gear, the com bination of an approximately horizontal bridge-piece forming a slideway, a slide block on said slideway, means for moving said block, an auxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links, each, having its lower end coupled to the auxiliary rod and ne having its upper end coupled to said side block and the other having itsupper end in operative relation with the distributing valve, substantially as described.

4. In a steam engine valve gear, the combination of an approximately horizontal bridge-piece forming a slideway, a slide block on said slideway, means for moving said slide block, a bell crank in operative relation with the distributing valve, an auxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links each having its lower end coupled to having its upper end coupled to .the bell crank, substantially as described.

bination of a bracket, a bell crank hinged to said bracket and being in operative relation with the distributing valve, a slide block, means for supporting said slide block, means for moving said slide block, an auxiliary crank, arr auxiliary rod, and two approximately upright links each having its lower end coupled to said auxiliary rodand one having its upper end coupled to said slide block and the other having its upper end coupled to said bell crank, substantially as described.

6. In a steam engine valve gear, the combination of a bracket, a bell crank supthe auxiliary rod and 'one'having its upperthe auxiliary -rodand one having itsupper end coupled to the slide block and the other.

5. In a steam engine valve gear, the com= ported by said bracket and being in operative relation with the distributing valve, 21 ln'idg'e piece having its rear end stmured to the engine framing and having its other end extended beneath said bell crank and se'trured to said bracket, the said bridgepiet'e having a slideway, a slide block on said slideway, means for moving said block, an auxiliary erank, an auxiliary rod coupled to billli crank, and two appruxr mately upright links eaeh havingits lower end coupled to the auxiliary rod and one having its upper end coupled to said slide hloek and the other having its upper end coupled to said bell crank, substantially described.

In testimony whereof I have signed my name, in presence of two witnesses, this 20th day of Junta in the year one thousand nine hundred and eleven.

Wl LLIA M SHERMAN 13R OWN.

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Units Kenn, l5. 0. OGLE. 

